CN112044431B - Method for loading metal nanocrystalline on amorphous nano material by one-step method - Google Patents

Method for loading metal nanocrystalline on amorphous nano material by one-step method Download PDF

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CN112044431B
CN112044431B CN202010922189.5A CN202010922189A CN112044431B CN 112044431 B CN112044431 B CN 112044431B CN 202010922189 A CN202010922189 A CN 202010922189A CN 112044431 B CN112044431 B CN 112044431B
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water
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王海龙
刘曼
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Abstract

The invention discloses a method for loading metal nanocrystalline on an amorphous nano material by a one-step method, which uses an iron-based modifier, utilizes the nanocrystalline attached on an amorphous nano core as a growth base point, epitaxially grows and coats a shell layer, directly loads the metal nanocrystalline on the surface of the amorphous nano core with high efficiency by the one-step method, and directly loads the ultra-small-size nanocrystalline on the surface of the amorphous nano core for the first time, thereby providing an effective feasible method for further synthesis and application of a nano composite material.

Description

Method for loading metal nanocrystalline on amorphous nano material by one-step method
The technical field is as follows:
the invention relates to the technical field of nano composite structure materials, in particular to a method for loading metal nanocrystals on an amorphous nano material by a one-step method.
Background art:
the nano core-shell structure is a composite mode of the nano composite material, and the composite material prepared by the core-shell structure can compound the characteristics of two or more materials, so that a rich composite mode is provided for the structure and characteristic design and application of the nano material. The load of the metal crystal nanocrystals on the amorphous nano-core material is always a research hotspot of the nano-composite structure material, and is different from the preparation of the nano-core-shell structure (metal nanoparticles are used as cores and amorphous materials are used as shell layers) in which the amorphous material is coated on the metal core, the load of the metal nano-crystal nano-composite material is difficult because the amorphous nano-particles are used as cores, and the problems that the direct load cannot be realized, the nanocrystal self-nucleation is realized, the load rate is low, the nanocrystal size is difficult to control, and the product concentration is low are faced. How to efficiently load nanocrystalline on amorphous crystals or crystals with different crystal forms to prepare a nanocomposite structure material with high load rate is always a research hotspot and difficulty in the field of nanocomposite material synthesis and preparation.
In the traditional 'layer-by-layer assembly method', connecting agents such as coupling agents, surface modifiers and the like are needed to respectively carry out surface modification on amorphous nano cores and nano crystals, and then the nano crystals are loaded on the surfaces of the cores through the successive action of the coupling agents and the surface modification. The mode of indirectly attaching or loading the nanocrystals by utilizing the interaction of the linking agent is difficult to load the nanocrystals with ultra-small sizes, has complex preparation process, multiple product influencing factors, low loading rate, long time consumption, low product concentration and difficult enlargement or large-scale preparation. The coupling agent, the surface modifier and other connecting agents are used for loading the nanocrystalline, so that a steric hindrance effect is easily formed, and meanwhile, the coupling agent and the surface modifier can also influence the surface characteristics of the nanocrystalline, such as catalysis, conductivity and the like, and are not beneficial to the application of products.
The invention content is as follows:
the invention aims to provide a method for loading metal nanocrystals on an amorphous nano material by a one-step method, which uses a ferrous-based modifier without using a connecting agent, utilizes the nanocrystals attached to an amorphous nano core as a growth base point, epitaxially grows and coats a shell layer, directly and efficiently loads metal nanocrystals on the surface of the amorphous nano core by the one-step method, and efficiently loads ultra-small-size nanocrystals on the surface of the amorphous nano core for the first time, so that an effective and feasible method is provided for further synthesis and application of a nano composite material.
The invention is realized by the following technical scheme:
a method for loading metal nanocrystals on an amorphous nanomaterial core in a one-step process, the method comprising the steps of:
dispersing amorphous nano materials in deionized water (DI water) or distilled water or ultrapure water to prepare a dispersion liquid with the concentration of 0.01-0.03mol/L, adding a ferrous (Fe (II)) based modifier with the concentration of 0.1-0.3mol/L, stirring for 0.5-2.5h, carrying out centrifugal washing at 3000-8000rpm according to the molar ratio of (2-5) to the ferrous (Fe (II)) based modifier in a reaction system, dispersing sediment in water after washing, carrying out ultrasonic dispersion and uniform stirring, adding a metal nano crystal precursor solution with the concentration of 0.05-0.3mol/L, violently stirring for 5-10min, reacting for 1-2h under an ultrasonic condition, carrying out centrifugal washing for three times by using water, dispersing in water to prepare a product dispersion liquid, and storing in a room.
The amorphous nanomaterial is selected from SiO 2 Any one of amorphous nano materials such as nanospheres, polystyrene microspheres, nano titanium oxide and nano carbon particles.
The modifier containing ferrous (Fe (II)) group is Fe 2+ The compound of (1), comprising: feSO 4 ·7H 2 O (ferrous sulfate), (NH) 3 ) 2 ·Fe(SO 4 ) 2 ·6H 2 O (ferrous ammonium sulfate), fe (NO) 3 ) 2 ·6H2O、2(C 2 H 3 O 2 ) Fe (ferrous acetate or acetate), fe (C) 2 O 4 )·2H 2 O (ferrous oxalate), ferrous gluconate, C 2 H 8 N 2 ·H 2 SO 4 ·FeSO 4 ·4H 2 O (ferrous ethylenediamine sulfate), feCl 2 ·4H 2 O、K 4 [Fe(CN) 6 ]·3H 2 O (potassium ferrocyanide) and Na 4 Fe(CN) 6 、Na 4 Fe(CN) 6 ·10H 2 Ferrous salts such as O and the like and ferrous complexing agents.
The reduction potential of the metal nanocrystalline precursor is larger than Fe 3+ /Fe 2+ (Fe (II)) reduction potential (0.358-0.771V) as describedThe metal nanocrystal comprises: ag. The reduction potential of the precursor of the nanocrystalline is higher than 0.358-0.771V.
The metal nanocrystals efficiently loaded on the amorphous nanomaterial core typically have a particle size of less than 25nm, and even ultra-small metal nanocrystals having a particle size of less than 10nm can be efficiently loaded.
When the amorphous nano material is SiO 2 When the nanosphere is used, the preparation method comprises the following steps: preparing a solution A and a solution B, wherein the solution A is formed by mixing Tetraethoxysilane (TEOS) and water; solution B from NH 3 ·H 2 O, water and absolute ethyl alcohol; mixing the solutions A and B, and stirring vigorously for 30min to obtain TEOS: NH 3 ·H 2 O:H 2 The molar concentration ratio of O to EtOH is 1 (0.8-1.5) to 0.4-0.8 (6-8), the reaction is carried out at 20-70 ℃ for 3h, the centrifugal absolute ethyl alcohol is washed for 2-3 times at 3000-8000rpm, the centrifugal sediment is dried at 105 ℃, and the amorphous SiO is prepared 2 Nanospheres. SiO can be regulated and controlled by regulating and controlling the proportion of reactants, the using amount of ammonia water and the reaction temperature 2 Particle size of nanospheres, siO 2 The particle size of the nanospheres is as follows: 30-500nm. SiO 2 2 The reaction can be expanded by 5-10 times during the preparation of the nanospheres.
Other amorphous nano-material polystyrene microspheres, nano titanium oxide, nano carbon particles and the like can be directly purchased into commercial products.
The invention also protects the application of the prepared nano composite material nanocrystal in catalysis, enhanced photocatalysis, biological medical treatment, ultraviolet and blue light protection.
The invention has the following beneficial effects: the method is characterized in that a ferrous-based modifier is used, a connecting agent is not needed, a nanocrystalline attached to an amorphous nano core is used as a growth base point, a shell layer is epitaxially grown and coated, the method for directly and efficiently loading the metal nanocrystalline on the surface of the amorphous nano core by a one-step method, and the ultra-small-size nanocrystalline is directly and efficiently loaded on the surface of the amorphous nano core for the first time, so that an effective feasible method is provided for further synthesis and application of a nano composite material.
Description of the drawings:
FIG. 1 is an amorphous SiO solid prepared in accordance with example 1 of the present invention 2 Nanospheres and high loading SiO prepared in example 3 2 -Scanning Electron Microscopy (SEM) comparison of AgNCs;
wherein a and b are amorphous nano material SiO prepared in example 1 2 SEM image of nanosphere (I-1 #); c, d are SiO as prepared in example 3 2 SEM picture of AgNCs (II-1 #).
FIG. 2 is an amorphous SiO solid prepared in example 2 of the invention 2 Nanospheres and high loading SiO prepared in example 4 2 SEM comparison of AgNCs;
wherein a and b are amorphous nano material SiO prepared in example 2 2 SEM image of nanosphere (I-2 #); c, d are SiO as prepared in example 4 2 SEM picture of AgNCs (II-2 #).
FIG. 3 shows the amorphous SiO nanomaterials of examples 3-4 of the present invention 2 X-ray diffraction (XRD) contrast before and after nanosphere loading;
wherein a is the amorphous SiO of example 3 2 XRD contrast diagram before and after loading of nanosphere (I-1 #); b is amorphous SiO as in example 4 2 (I-2 #) XRD contrast before and after loading.
FIG. 4 is a diagram showing SiO for the product of example 3 2 SEM comparison of the long-term stability of AgNCs (II-1 #);
wherein a-c is initial SiO 2 -low to high power SEM of AgNCs (II-1 #); d-f is SiO after long-term storage 2 -low to high power SEM for AgNCs (II-1 #).
FIG. 5 is SiO, a product of example 3 2 SEM-EDS after long-term storage for more than 33 months for AgNCs (II-1 #).
FIG. 6 is SiO, a product of example 3 2 -TEMs with high loading rate and long-term stability of AgNCs (II-1 #);
wherein a-c is SiO with the storage period of more than 33 months 2 -low to high TEM of AgNCs (II-1 #); d is SiO 2 High Resolution TEM (HRTEM) of Ag nanocrystals loaded on AgNCs, partially embedded in amorphous SiO 2 The spacing between crystal planes of the crystal lattice stripes is 0.24nm and corresponds to a (111) crystal plane of Ag; e-g is SiO 2 -AgNCs (II-1 #) high angle annular dark field-scanning transmission electron microscope (HAADF-STEM) pictures from low to high magnification, amorphous SiO 2 The particle sizes of the nano-spheres and the Ag nano-crystals are 190-210nm and 3-25nm respectively; h-k is SiO 2 -DEX imaging of AgNCs; l is a cross section of the distribution of the content of the line scanning element corresponding to h; m is single SiO 2 AgNCs corresponds to h single SiO 2 EDS by AgNCs, inset by element content; n is a content curve of the line scanning element corresponding to l, and is sequentially O, si and Ag.
FIG. 7 is SiO for the product of example 4 2 SEM comparison of the long-term stability of AgNCs (II-2 #);
wherein a-c is initial SiO 2 -low to high power SEM of AgNCs (II-2 #); d-f is SiO after long-term storage 2 -low to high power SEM for AgNCs (II-2 #). SiO of high-load Ag nano crystal 2 AgNCs (II-2 #) has long-term stability, amorphous SiO 2 Ag nano crystal loaded on the nanosphere is partially embedded in SiO 2 In the nano-sphere, partial crystals of the Ag nano-crystals are embedded in SiO 2 On the nanosphere, the nanosphere is not easy to fall off, and partial crystals of Ag nanocrystal are embedded or adsorbed on SiO 2 On the nanospheres, the surface potential of the portion of the crystal that interacts with the nanospheres is reduced and the total surface area of the exposed Ag nanospheres is reduced, resulting in a reduction in SiO 2 -total potential energy of Ag nanocrystals loaded on AgNCsReduced, enhanced stability, and formation of a strong, stable amorphous-crystalline composite structure. SiO 2 2 The stable storage period of AgNCs (II-2 #) is more than 33 months.
FIG. 8 is SiO, a product of example 4 2 SEM-EDS after long-term storage for more than 33 months for AgNCs (II-2 #).
FIG. 9 is SiO, a product of example 4 2 -TEMs with high loading rate and long-term stability of AgNCs (II-2 #);
wherein a-c is SiO with the storage period of more than 33 months 2 -low to high TEM of AgNCs (II-2 #); d is SiO 2 High Resolution TEM (HRTEM) of Ag nanocrystals loaded on AgNCs, partially embedded in amorphous SiO 2 The spacing between crystal planes of the crystal lattice stripes is 0.24nm and corresponds to a (111) crystal plane of Ag; e-g is SiO 2 -AgNCs (II-2 #) high angle annular dark field-scanning transmission electron microscope (HAADF-STEM) picture from low to high magnification, the grain size of the nanocore and Ag nanocrystal being 210-230nm and 5-25nm, respectively; h-k is SiO 2 -DEX imaging of AgNCs; l is a cross section of the distribution of the content of the line scanning element corresponding to h; m is single SiO 2 AgNCs corresponds to h single SiO 2 EDS by AgNCs, inset by element content; n is a content curve of the line scanning element corresponding to l, and is sequentially O, si and Ag.
FIG. 10 shows the high-loading ultra-small-sized nanocrystalline SiO prepared in example 5 of the present invention 2 -AgNCs(SiO 2 : 500nm, agNCs:5-10 nm).
FIG. 11 is a UV-VIS-NIR absorbance spectrum of the products of example 1 and example 3;
wherein a is example 1 (SiO) 2 (I-1 #)) and example 3 (SiO) 2 -AgNCs # (II-1))) dispersions, milky white and reddish brown respectively; b is the UV-Vis-NIR absorbance spectra of the products of example 1 and example 3. Amorphous SiO 2 The nanosphere has no absorption peak at 200-1200nm, has strong absorption peak at 200-1200nm after loading silver nanocrystal, has high absorbance at 448nm and 340-560nm, strongly absorbs ultraviolet rays, has ultraviolet and blue light protection function, and enhances photocatalysis.
The specific implementation mode is as follows:
the following is a further description of the invention and is not intended to be limiting.
Example 1: preparation of amorphous SiO 2 Nanosphere (particle size: 200 + -10 nm)
Amorphous SiO 2 Preparing nanospheres by preparing solution A and solution B, wherein solution A is prepared from 3.17ml TEOS and 25ml H 2 O is mixed; solution B from 2.52ml (25 wt%) NH 3 ·H 2 O and 1.8ml H 2 O and 25ml EtOH; mixing solution A and B, stirring vigorously for 30min, reacting at 50 deg.C for 3h, centrifuging at 5000rpm for anhydrous ethanol for 2-3 times, drying the centrifugal precipitate at 105 deg.C to obtain amorphous SiO 2 Nanospheres (record as I-1#, particle size: 200 + -10 nm). SiO 2 2 Scanning Electron Microscopy (SEM) images of nanospheres see a, b, siO in FIG. 1 2 The reaction can be expanded by 5-10 times during the preparation of the nanospheres.
Example 2: preparation of amorphous SiO 2 Nanosphere (particle size: 220 + -10 nm)
Reference example 1, except that SiO 2 Nanosphere (I-2 #, particle size: 220. + -.10 nm) 3.78ml (25 wt%) NH was used 3 ·H 2 O is reacted for 3h at room temperature, and the Scanning Electron Microscope (SEM) images of the reaction solution are shown as a, b and SiO in FIG. 2 2 The reaction can be expanded by 5-10 times during the preparation of the nanospheres.
Example 3: preparation of highly loaded SiO 2 -AgNCs(II-1#)
0.72g of SiO prepared in example 1 2 The nanospheres were dispersed in 30ml deionized water, 30ml 0.15MK 4 [Fe(CN) 6 ]·3H 2 Stirring for 1h with O, centrifuging at 5000rpm for 3 times, dispersing the washed sediment in 30ml of DI water, ultrasonically dispersing and uniformly stirring, adding 15ml of 0.175mol/L silver ammonia solution, violently stirring for 5-10min, reacting for 1h under ultrasonic condition, centrifuging and washing for three times with DI water, and dispersing in 30ml of DI water to obtain SiO 2 -AgNCs (II-1 #) dispersion, siO of load nanocrystal 2 The dispersion liquid presents milk white and efficiently loads nanocrystalline SiO 2 The AgNCs dispersion appeared reddish brown due to localized surface plasmon resonance effects of the silver nanocrystals. High-load SiO 2 Scanning Electron Microscopy (SEM) of AgNCs FIGS. 1 (c, d) and 5, siO 2 Preparation of AgNCsThe reaction can be expanded by 3-5 times when preparing.
Example 4: preparation of highly loaded SiO 2 -AgNCs(II-2#)
Reference example 3 with the exception that the SiO prepared in example 2 was used 2 Nanospheres, siO prepared by adding silver ammonia solution and reacting for 2h 2 The AgNCs (II-2 #) dispersion is stored indoors for later use. High-load SiO 2 Scanning Electron Microscopy (SEM) of AgNCs FIGS. 2 c, d and 8, siO 2 The reaction can be expanded by 3-5 times when the AgNCs is prepared.
Example 5: preparation of high-load ultra-small-size nanocrystalline SiO 2 -AgNCs(SiO 2 ：～500nm,AgNCs：5-10nm)
Reference example 3, except that 30ml of 0.2mol/LFe (II) -based modifier (FeCl) was added 2 ·4H 2 O) was stirred for 2h, and 15ml of a 0.3mol/L silver ammonia solution was added. High-load ultra-small-size nanocrystalline SiO 2 AgNCs, amorphous SiO 2 The particle size of the nanospheres is 500nm, the particle size of the loaded ultra-small silver nanocrystal is 9.08 +/-1.91 nm, and the high-load SiO is 2 A high angle annular dark field image (HAADF-STEM) map of AgNCs is shown in FIG. 9. High load rate, uniform size, and ultra-small size of the nanocrystal.
Example 6:
reference example 4 was made except that SiO was replaced with any one of polystyrene microspheres, nano titanium oxide and nano carbon particles 2 Nanospheres.
Example 7: siO 2 2 High load factor, stability and optical Properties of AgNCs
The nano-crystal loaded on the amorphous nano-material by the method has high loading rate, strong stability and specific optical characteristics. The products of example 3 and example 4, having a pot life of more than 33 months, were characterized by Scanning Electron Microscopy (SEM), transmission Electron Microscopy (TEM) and high-angle annular dark-field-scanning transmission electron microscopy (HAADF-STEM) and analyzed for element content by EDS. Optical properties of the amorphous nanomaterial before and after loading were measured using an ultraviolet-visible-near infrared spectrophotometer. As can be seen from FIG. 4, siO highly loaded with Ag nanocrystals 2 AgNCs (II-1 #) has long-term stability, SiO 2 The upper loaded Ag nano crystal is partially embedded in SiO 2 Inner, siO 2 -AgNCs (II-1 #) stable shelf life greater than 33 months. The method has high nanocrystalline loading rate on the amorphous nano material, and the nanocrystalline loading rate is more than 14% (see fig. 5 and fig. 8). As can be seen from FIG. 5, siO 2 SiO with long-term stability and high Ag nanocrystalline loading for AgNCs (II-1 #) 2 SEM-EDS for AgNCs (II-1 #). SiO 2 2 DES after storage of AgNCs for more than 33 months, the elemental content of Ag being indicative of SiO 2 The Ag nanocrystals loaded by the AgNCs have high loading rate, and the nanocrystal loading rate is more than 14 percent. As can be seen from FIG. 8, siO 2 SiO with long-term stability and high Ag nanocrystalline load by AgNCs (II-2 #) 2 SEM-EDS for AgNCs (II-2 #). SiO 2 2- DES after AgNCs storage for more than 33 months, the elemental content of Ag indicates SiO 2 The Ag nanocrystals loaded by the AgNCs have high loading rate, and the nanocrystal loading rate is more than 14 percent. The EDS of the individual nanomaterials prepared in example 3 showed supported nanocrystal contents greater than 20wt% (see h-n in FIG. 6 and h-n in FIG. 9). Example 4 the reaction time for loading the nanocrystals was extended and the product loading nanocrystal content was further increased to 24.42wt% (h-n in fig. 9).
It is noted that the nanocrystalline partial crystal loaded by the method of the invention is embedded on the surface of the amorphous body (see a-d in figure 6 and a-d in figure 9), is not easy to fall off, has strong structural stability and chemical stability, and can be stored for a long time (see figure). Figures 4-9 show that dispersions of the product can be stored stably for long periods of time in the room, with a shelf life of greater than 33 months. And partial crystals of the nanocrystals are inlaid or adsorbed on the amorphous nanomaterial, the surface potential energy of the partial crystals under the action of the nanocrystals is reduced, the total surface area exposed by the Ag nanospheres is reduced, the total potential energy of the loaded nanocrystals on the product is reduced, the activity of the nanocrystals is maintained, the stability is enhanced, and a firm and stable amorphous-crystal composite structure is formed.
After the amorphous nano material is loaded with the nano crystal efficiently, a strong surface plasma resonance effect is formed, and an absorption spectrum has a strong resonance absorption peak (see b in fig. 11). SiO 2 2 The optical properties of AgNCs are mainly reflected in the supported nanocrystals, siO 2 Due to the fact that a large number of Ag nanocrystals are loaded, the comparative amorphous nano material has no absorption peak in an ultraviolet-visible-near infrared light region (250-1200 nm), after the nanocrystals are loaded, a sharp single Local Surface Plasmon Resonance (LSPR) absorption peak appears, the peak position of the absorption peak is 448nm (see b in figure 11), and SiO 2 The absorption peak of AgNCs is generated by Ag nanocrystals loaded by the AgNCs. The light absorption range is 340-560nm, the ultraviolet light and the blue light are strongly absorbed, and the ultraviolet light and the blue light are protected and the photocatalysis function is enhanced. Before and after loading the nanocrystalline on the amorphous body, due to the local surface plasmon resonance effect of the loaded noble metal nanocrystalline, the dispersion liquid of the loaded product shows obvious color change compared with the dispersion liquid without loading the nanocrystalline. Example 3 the amorphous dispersion without supported nanocrystals was milky white, with a significant color change after supported nanocrystals, and the dispersion appeared reddish brown (a in fig. 11). Meanwhile, the loaded nanocrystal has small size, large specific surface area and strong catalytic activity, is suitable for catalysis and has wide application.

Claims (6)

1. A method for loading metal nanocrystals on an amorphous nanomaterial core by a one-step process, the method comprising the steps of:
dispersing an amorphous nano material in deionized water, distilled water or ultrapure water to prepare a dispersion liquid with the concentration of 0.01-0.03mol/L, adding a ferrous modifier with the concentration of 0.1-0.3mol/L, stirring for 0.5-2.5h, carrying out centrifugal washing at 3000-8000rpm according to the molar ratio of (2-5) to the ferrous modifier in a reaction system, dispersing the washed sediment in water, carrying out ultrasonic dispersion and stirring uniformly, adding a metal nanocrystalline precursor solution with the concentration of 0.05-0.3mol/L, stirring vigorously for 5-10min, reacting for 1-2h under the ultrasonic condition, carrying out centrifugal washing three times by using water, dispersing in water to prepare a product dispersion liquid, and preparing a nanocomposite nanocrystal and placing in a room for storage; the grain size of the metal nanocrystalline efficiently loaded on the amorphous nano material core is less than 25nm;
the amorphous nano material is selected from SiO 2 Any one of nanospheres, polystyrene microspheres, nano titanium oxide and nano carbon particles;
the ferrous modifier is Fe-containing 2+ A compound of (1);
the reduction potential of the metal nanocrystalline precursor is larger than Fe 3+ /Fe 2+ A reduction potential;
the metal nanocrystalline is selected from any one of Ag, au, pt, pd, ru and Rh nanocrystalline.
2. The one-step method for loading metal nanocrystals onto an amorphous nanomaterial core according to claim 1, wherein the ferrous modifier is selected from ferrous salts or ferrous complexing agents.
3. The one-step method for loading metallic nanocrystals onto amorphous nanomaterial cores according to claim 1 or 2, wherein the ferrous modifier is selected from FeSO 4 ·7H 2 O、(NH 4 ) 2 ·Fe(SO 4 ) 2 ·6H 2 O、Fe(NO 3 ) 2 ·6H 2 O、Fe(C 2 H 3 O 2 ) 2 、Fe(C 2 O 4 )·2H 2 O, ferrous gluconate, C 2 H 8 N 2 ·H 2 SO 4 ·FeSO 4 ·4H 2 O、FeCl 2 ·4H 2 O 、K 4 [Fe(CN) 6 ]·3H 2 O、Na 4 Fe(CN) 6 、Na 4 Fe(CN) 6 ·10H 2 O。
4. The method of one-step method for loading metal nanocrystals onto an amorphous nanomaterial core according to claim 1 or 2, wherein the metal nanocrystals efficiently loaded onto the amorphous nanomaterial core have a particle size of less than 10 nm.
5. The method of claim 1 or 2, wherein the SiO is loaded with metal nanocrystals on an amorphous nanomaterial core by a one-step process 2 The preparation method of the nanosphere comprises the following steps: preparing a solution A and a solution B, wherein the solution A is formed by mixing tetraethoxysilane and water; solution B from NH 3 ·H 2 O, water and absolute ethyl alcohol; mixing the solution A and the solution B, and then violently stirring to obtain the solution containing the tetraethoxysilane NH 3 ·H 2 O, water and absolute ethyl alcohol with the molar concentration ratio of 1 (0.8-1.5) to 0.4-0.8 to 6-8, reacting at 20-70 ℃ for 3h, washing with centrifugal absolute ethyl alcohol at 3000-8000rpm for 2-3 times, and drying the centrifugal sediment at 105 ℃ to obtain amorphous SiO 2 Nanospheres of SiO 2 The particle size of the nanospheres is as follows: 30-500nm.
6. The application of the nano composite material nanocrystal in catalysis, enhanced photocatalysis, preparation of biomedical materials and ultraviolet and blue light protection is characterized in that the nano composite material nanocrystal is prepared by the method of loading metal nanocrystals on an amorphous nanomaterial core by the one-step method in claim 1.
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